I have an old H/P 5245L counter with an OPT H91, what is the H91 opt? Can not seem to find any reference for this opt. Thanks,Ray
I may be wrong, because it has been awhile since I have used one of these. I think it may be the High Voltage option. I may be wrong, but that's my guess.
The H91 option was to get the manual on parchment paper instead of the usual stone tablet... :-D
I couldn't pass that one up...
Seriously, the best source for old test equipment and the various options is the HP catalogs - you can find them on eBay for about $10 or so.
http://cgi.ebay.com/HP-1979-Test-Measurement-Catalog_W0QQitemZ250088882329QQihZ015QQcategoryZ25409QQssPageNameZWDVWQQrdZ1QQcmdZViewItem